In the current era of digital transformation, the concept of a “Stand Alone” product is staring at irrelevance. Most applications are made accessible from different hand-held devices and are connected via the internet. This is not a protocol but to match the technological agility, it has become an ideal standard because of the growing expectations of the customers and pressure of the emerging startups.

With the growing need for web applications, concerns like security and interoperability are taking the center stage in the mind of developers. The problem to be solved was the usage of different programming languages and the complexity of setting up proper communication channels between them.

It is rightly said that “necessity is the mother of invention” and as the problem grew, out came the solution of independent web services. These web services were designed to act independently underlying the operating system, programming languages and varieties of handheld devices.

They were designed with a motive to exchange structured information between the client and the server amongst the hand-held devices on the internet. Two such formats of web services are:

REST- Representational State Transfer.

SOAP- Simple Object Access Protocol.

SOAP:

As the name suggests, SOAP is an object-access protocol that has been based on XML information set to translate information in the message format. To describe the SOAP toolkit, WSDL (Web Service Description Language) was introduced. SOAP works well with the computer systems as it allows processes to communicate that are running on different OS such as Windows and Linux. But even though SOAP was favored earlier, it was replaced by REST due to the following limitations:

SOAP is a protocol and because of that, it does not favor frequent changes. To change services, complex code changes are required on the client side. Thus, it becomes a major problem for mobile applications that uses the SOAP client as there are frequent updates to be made.

Generating new code for SOAP client from WSDL can be really complex. Also, when mobile applications are built as cross-platform, there arises the need to do manual coding on the client's part. It is a time-consuming process and is also prone to errors.

Although SOAP as a protocol has set certain security standards, SOAP is also transport-independent and there can be no assumptions made about the security available on transport layers. Thus, it has some security issues as well.

It is based on XML only.

Although SOAP and REST were developed and marketed at almost the same time, REST has gained much more popularity and trust because of the limitations of SOAP and adaptable nature of REST.

REST:

REST, or RESTful web service, is an architectural style of designing to provide interoperability between different hand-held devices and applications on the internet. It was defined by Roy Fielding as an architecture and uses HTTP/HTTPS as the means of communication. Due to its ability to deliver a fast, scalable and easy to maintain web service, REST gained huge favors amongst the developers.

Before jumping to why REST is favored, let’s first understand how REST works. REST is based on three pillars:

Resources:

REST recognizes the URIs (Unique Resource Identifier) and establishes the best way to reach to them on the web, e.g. URL (Unique Resource Locator). REST uses HTTP or HTTPS as a medium of communication between a client and a server. Different URLs can be designed to reach to the same resource and extract only requested information from the resource.

Verbs:

To extract different information from a resource, an action needs to carried out via an HTTP request. To make that happen, there are different HTTP action or verb in REST terminologies such as POST, GET, PUT, DELETE, OPTIONS, etc.

Thus, when a user requests for a certain information from the host, verbs interpret and analyze the request to present the requested data to the user.

Representations:

The final pillar is the way to represent the resources to the clients. As the RESTful web service is an architecture, it works perfectly in any format like JSON, XML etc. without any restrictions.

Now that the understanding of the RESTful web service is clear, let's understand why REST is more favored.

REST is more favored because it is:

Simple- REST is designed to work between different clients like web browsers, networking equipment as well as various service types such as Ruby, JAVA and .NET.

Cacheable- REST is well suited to caching as the URL analyze the exact request and with the network caching infrastructure, it can respond with a correct answer.

Efficient- While SOAP only responds only in XML, REST can respond in many different response formats like the heavy XML data can be displayed in a PNG file as well. Due to its base on JSON, the payloads are usually smaller than XML counterparts.

But, this doesn’t prove that REST is perfect; every yin has a yang and REST also has certain limitations.

No Standard Format:

REST works on URLs and the designing of URLs can be done in many ways depending on the need and size of the application. Because of this, developers sometimes fail to rationalize and instead choose a long way that might lead to errors in defining the right URL for the requested information from the resource.

REST is an architecture and because of that, there are no set standards. It can be easily transported and that is the reason software engineers have to work on the security of the information to make sure the PII data is not transmitted to systems that cannot be trusted.

But a developer would agree when I say that these are more like an extended checklist rather than limitations of application development. The RESTful web services offer endless possibilities to establish communication between different clients and the server of your product.

When implemented properly, REST offers the best of performance, robustness, and bandwidth efficiency. It also increases a developer’s productivity and creates an opportunity to set up optimum security.